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Isn't "In zero wind conditions, L/D will equal altitude lost divided by distance traveled" backwards?
The article says that maximum range is at minimum drag???
Shouldn't this be minimum drag per unit distance? WolfKeeper 16:53, 24 August 2007 (UTC)
The explanation for induced drag in the article is wrong: lift is not defined as the force perpendicular to the wing (whatever reference line), but perpendicular to the free stream direction. Thus, induced drag cannot be explained as a consequence of the wing flying at an AOA, tilting the lift backwards. Actually, induced drag is zero for a two-dimensional wing or wing of infinite span. Induced drag is the result of the additional downwash induced by the tip vortices. This causes the wing to see a different averaged free stream which is angled downward. Furthermore, best L/D occurs at minimum drag since this drag graph is calculated for constant lift (i.e. level flight). So it is wrong to say that at slower speed there is less lift.— Preceding unsigned comment added by JaRaMW ( talk • contribs) 07:49, 31 May 2011 (UTC)
It's right that these drop in supersonic flight; it is the result of wave drag due to lift, absent when compressibility is not an issue. But I don't think the comparison of two different aircraft travelling at subsonic and supersonic speeds is helpful. In addition, the aerodynamics of a delta wing, even at low speeds is very different from straight or swept ones, as there are vortices not just at the tips but all along the leading edge. Much better if we can get data for one aircraft, perhaps ideally with straight wings, in the two regimes. There is a plot of CD,0 for the T-38 at 0.2 < M < 1.4 in Anderson's Aircraft Performance and Design (it increases by a factor of about 3) but no CL. Must be out there somewhere! TSRL ( talk) 19:24, 27 October 2011 (UTC)
The lede contains a statement that Lift-to-drag ratios are usually found using a wind tunnel. The cited source is NASA. This statement is also found in Flight. Its validity is presently under discussion at Talk:Flight#Lift-to-drag ratio. Dolphin ( t) 08:02, 11 May 2012 (UTC)
eg. {{glide ratio examples}} - Rod57 ( talk) 02:21, 7 December 2014 (UTC)
A quick calculation shows the value of 7 for the C150 in cruise is too low, by at least 30 percent. No source is given. Can someone improve this entry? Thanks in advance.-- Spray787 ( talk) 01:36, 4 June 2015 (UTC)
It is not polar coordinates, so why is it called a polar plot? 2600:1700:4CA1:3C80:2536:CFC6:40D7:3026 ( talk) 23:02, 22 August 2020 (UTC)
I was looking for the L/D for flat rectangular plates at various AoA, but nothing here or at Lift (force). - Rod57 ( talk) 11:22, 9 December 2020 (UTC)
95.91.246.145 ( talk) 05:31, 2 January 2022 (UTC)
@Ariadacapo: It would show respect and be helpful, if you have read my edits and comments, best have some knowledge about aviation and L/D ratio. And please focus on the content of the article! And i do not like the prejudicing, that an IP-editor has to prove his "believes", whereas an registered editor can publish unproven nonsense:
A: "The angle of the tether displays the dramatic improvement of the lift-to-drag ratio."
Prove it! ANSWER!
B: The schematic pic below shows OBVIOUSLY aerodynamic force, nothing with L/D ratio
See my comments:
Ever flown a kite? Airspeed and angle-of-attack are other articles, different! Angle of tether has even less to do with this topic. QED
Show respect, that means read and try to understand before giving advice! 95.91.246.145 ( talk) 12:24, 2 January 2022 (UTC)
The wright pic was illustrating the article since a long time. It shows the total aerodynamic force direction, through the tether. The total aerodynamic force is subdivised in lift and drag, as explained in the schematic. The angle of the aero. force shows the relation between both components, and the improved angle shows the gain in L/D ratio. It's a good illustration:
The picture is about aerodynamic force, not AoA. The tether shows the relation between two vectors through its angle. It does not shows the AoA.-- Marc Lacoste ( talk) 12:37, 2 January 2022 (UTC)
Solution:
Revert to the last state edited by me:
95.91.246.145 ( talk) 16:03, 2 January 2022 (UTC)
I have come here because it has been raised on the Project talk page (thank you for that, MelanieN). The best way ahead here is to remain calm, respect the WP:CIVIL pillar of our editing community, and pick off the issues of disagreement one at a time. No more "You started it, you invaded Poland!" type personal rhetoric. Just the salient points in making this encyclopedia better.
So, to take the lead image of the Wright flyer. I agree with the IP editor that the caption does not make clear the link between AoA and l/d. Nor should it; if AoA is to be used as a discussion point, that should be done in the main text and not in an image caption. Nor should the lead image attempt to depict such a secondary relationship. The fact that it has been here a long time is irrelevant, it needs to either go lower down near the associated discussion, or be deleted. I propose that for now it should be moved down to the section on drag (that section is no better in technical clarity than the current image caption, but this one change is enough for a first discussion).
— Cheers, Steelpillow ( Talk) 20:35, 2 January 2022 (UTC)
This diagram has been subject to edit warring:
I think it is a good candidate for the article lead, as it defines the two forces the article is about. But the caption could be improved. I'd propose something like, "Lift and drag are the two components of the total aerodynamic force acting on an aerofoil or aircraft".
I suggest "aerofoil or aircraft" advisedly, as l/d is often specified for a given aerofoil over a range of AoA and perhaps also airspeeds, while on the other hand for a sailplane it is typically given for the whole aircraft and dictates the glide angle. This is something the article will eventually need to explain.
— Cheers, Steelpillow ( Talk) 14:24, 3 January 2022 (UTC)
This image is also the subject of controversy:
My own view is that it does not support the section it is currently in, viz. Examples of L/D ratios, because it shows lift-minus-weight vs drag and not lift alone vs drag. Also, the presence or otherwise of dynamic (acceleration) effects is not clear. Nor can I see any other section it is more suited to. Therefore it should be deleted. What do others think? — Cheers, Steelpillow ( Talk) 18:39, 4 January 2022 (UTC)
Participate if you want. 95.91.246.145 ( talk) 08:19, 5 January 2022 (UTC)
![]() | This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||||||
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Isn't "In zero wind conditions, L/D will equal altitude lost divided by distance traveled" backwards?
The article says that maximum range is at minimum drag???
Shouldn't this be minimum drag per unit distance? WolfKeeper 16:53, 24 August 2007 (UTC)
The explanation for induced drag in the article is wrong: lift is not defined as the force perpendicular to the wing (whatever reference line), but perpendicular to the free stream direction. Thus, induced drag cannot be explained as a consequence of the wing flying at an AOA, tilting the lift backwards. Actually, induced drag is zero for a two-dimensional wing or wing of infinite span. Induced drag is the result of the additional downwash induced by the tip vortices. This causes the wing to see a different averaged free stream which is angled downward. Furthermore, best L/D occurs at minimum drag since this drag graph is calculated for constant lift (i.e. level flight). So it is wrong to say that at slower speed there is less lift.— Preceding unsigned comment added by JaRaMW ( talk • contribs) 07:49, 31 May 2011 (UTC)
It's right that these drop in supersonic flight; it is the result of wave drag due to lift, absent when compressibility is not an issue. But I don't think the comparison of two different aircraft travelling at subsonic and supersonic speeds is helpful. In addition, the aerodynamics of a delta wing, even at low speeds is very different from straight or swept ones, as there are vortices not just at the tips but all along the leading edge. Much better if we can get data for one aircraft, perhaps ideally with straight wings, in the two regimes. There is a plot of CD,0 for the T-38 at 0.2 < M < 1.4 in Anderson's Aircraft Performance and Design (it increases by a factor of about 3) but no CL. Must be out there somewhere! TSRL ( talk) 19:24, 27 October 2011 (UTC)
The lede contains a statement that Lift-to-drag ratios are usually found using a wind tunnel. The cited source is NASA. This statement is also found in Flight. Its validity is presently under discussion at Talk:Flight#Lift-to-drag ratio. Dolphin ( t) 08:02, 11 May 2012 (UTC)
eg. {{glide ratio examples}} - Rod57 ( talk) 02:21, 7 December 2014 (UTC)
A quick calculation shows the value of 7 for the C150 in cruise is too low, by at least 30 percent. No source is given. Can someone improve this entry? Thanks in advance.-- Spray787 ( talk) 01:36, 4 June 2015 (UTC)
It is not polar coordinates, so why is it called a polar plot? 2600:1700:4CA1:3C80:2536:CFC6:40D7:3026 ( talk) 23:02, 22 August 2020 (UTC)
I was looking for the L/D for flat rectangular plates at various AoA, but nothing here or at Lift (force). - Rod57 ( talk) 11:22, 9 December 2020 (UTC)
95.91.246.145 ( talk) 05:31, 2 January 2022 (UTC)
@Ariadacapo: It would show respect and be helpful, if you have read my edits and comments, best have some knowledge about aviation and L/D ratio. And please focus on the content of the article! And i do not like the prejudicing, that an IP-editor has to prove his "believes", whereas an registered editor can publish unproven nonsense:
A: "The angle of the tether displays the dramatic improvement of the lift-to-drag ratio."
Prove it! ANSWER!
B: The schematic pic below shows OBVIOUSLY aerodynamic force, nothing with L/D ratio
See my comments:
Ever flown a kite? Airspeed and angle-of-attack are other articles, different! Angle of tether has even less to do with this topic. QED
Show respect, that means read and try to understand before giving advice! 95.91.246.145 ( talk) 12:24, 2 January 2022 (UTC)
The wright pic was illustrating the article since a long time. It shows the total aerodynamic force direction, through the tether. The total aerodynamic force is subdivised in lift and drag, as explained in the schematic. The angle of the aero. force shows the relation between both components, and the improved angle shows the gain in L/D ratio. It's a good illustration:
The picture is about aerodynamic force, not AoA. The tether shows the relation between two vectors through its angle. It does not shows the AoA.-- Marc Lacoste ( talk) 12:37, 2 January 2022 (UTC)
Solution:
Revert to the last state edited by me:
95.91.246.145 ( talk) 16:03, 2 January 2022 (UTC)
I have come here because it has been raised on the Project talk page (thank you for that, MelanieN). The best way ahead here is to remain calm, respect the WP:CIVIL pillar of our editing community, and pick off the issues of disagreement one at a time. No more "You started it, you invaded Poland!" type personal rhetoric. Just the salient points in making this encyclopedia better.
So, to take the lead image of the Wright flyer. I agree with the IP editor that the caption does not make clear the link between AoA and l/d. Nor should it; if AoA is to be used as a discussion point, that should be done in the main text and not in an image caption. Nor should the lead image attempt to depict such a secondary relationship. The fact that it has been here a long time is irrelevant, it needs to either go lower down near the associated discussion, or be deleted. I propose that for now it should be moved down to the section on drag (that section is no better in technical clarity than the current image caption, but this one change is enough for a first discussion).
— Cheers, Steelpillow ( Talk) 20:35, 2 January 2022 (UTC)
This diagram has been subject to edit warring:
I think it is a good candidate for the article lead, as it defines the two forces the article is about. But the caption could be improved. I'd propose something like, "Lift and drag are the two components of the total aerodynamic force acting on an aerofoil or aircraft".
I suggest "aerofoil or aircraft" advisedly, as l/d is often specified for a given aerofoil over a range of AoA and perhaps also airspeeds, while on the other hand for a sailplane it is typically given for the whole aircraft and dictates the glide angle. This is something the article will eventually need to explain.
— Cheers, Steelpillow ( Talk) 14:24, 3 January 2022 (UTC)
This image is also the subject of controversy:
My own view is that it does not support the section it is currently in, viz. Examples of L/D ratios, because it shows lift-minus-weight vs drag and not lift alone vs drag. Also, the presence or otherwise of dynamic (acceleration) effects is not clear. Nor can I see any other section it is more suited to. Therefore it should be deleted. What do others think? — Cheers, Steelpillow ( Talk) 18:39, 4 January 2022 (UTC)
Participate if you want. 95.91.246.145 ( talk) 08:19, 5 January 2022 (UTC)